Three people were shot dead in their homes within the space of a day.
When the police interview the 15-year-old who is suspected of having organised the murders, he cannot stop laughing.
So, walla, you're really funny, he says to the interrogator.
The boys meet at a foster home in central Sweden. According to the indictment, it is there that the 15-year-old gives the 16-year-old the assignment to kill.
In October, the duo escapes from the home. A few days later, three people have been brutally murdered in southern Stockholm.
On 12 October, a masked shooter, armed with an automatic weapon, breaks into a villa in Västberga and shoots dead a 40-year-old father. A woman and a child are injured by gunfire.
A day later, the 16-year-old is arrested with the murder weapon in a taxi, minutes after two women have been shot dead in a villa in Tullinge.
The 15-year-old is arrested the next day, suspected of having instigated the murders. His girlfriend, also 15, is arrested on suspicion of aiding and abetting murder. The couple had spent the day at the Mall of Scandinavia, where they had bought clothes for 25,000 kronor in cash.
"Big Brother"
The murder assignments seem to come from a person the 15-year-old calls "big brother". In chats, he describes him as the father he never had.
After the murder in Västberga, he writes excitedly that his "dealer" ran in with a Kalashnikov rifle and "wiped out someone's dad and mum".
"Inshallah, my beloved brother, you have done well", writes the client.
"Bro, yeah, I'm really glad to make you proud", replies the 15-year-old.
Loyalty and violence, writes the boy, are the only things he can do.
After the double murder the next day, he is ecstatic.
"Fkn hell, I'm really glad".
Laughing
The boy was taken into care by social services at the age of 13. The police see him in the company of heavily criminal individuals, for whom he is believed to act as a runner, and on his phone, there are pictures of him posing with weapons.
Hardly two years later, he is sitting in an interrogation room, suspected of instigating three murders and seven attempted murders. He mostly answers "no comment", but unlike his co-defendants, he does not seem to be affected by the gravity of the situation.
Time and again, he bursts out laughing.
You understand that this is about three people who have been murdered, asks the interrogator.
I have twitches, he says.
"Going to stop killing"
In a seized letter sent from the remand prison, he writes, according to the police, about his future plans and that he is counting on a "four", four years of closed youth care.
"Either I'll escape directly from the remand prison or I'll do my time", he writes, and adds:
"When I get out, I'll stop killing people. I think I'll focus more on para. Drugs and that sort of thing".
The trial is ongoing behind closed doors at the Södertörn District Court. On Tuesday, the surviving family members of the victims will be heard.